JP2008191076A - Corrosion monitoring device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a corrosion monitoring device capable of automatically monitoring corrosion of a structure, such as a bridge, measuring corrosion acceleration of corrosion environment, and, in addition, reducing personnel expenditure concerned with maintenance management of a structure. <P>SOLUTION: The monitoring device comprises an coated optical fiber 4 for strain measurement with tension applied in a longitudinal direction and a corrosion monitoring member 5 connected to the coated optical fiber 4 so as to retain the strain of the coated optical fiber 4 for strain measurement, in which the coated fiber 4 is optically connected to a scattered light analyzer 6 via a communicating coated optical fiber 7, and the scattered light analyzer 6 detects changes in the strain of the coated optical fiber 4 for strain measurement that is relaxed under the condition with the corrosion monitoring member 5 corroded, thereby judging the corrosion of the member 5. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a corrosion monitoring apparatus that is employed for monitoring corrosion of structures such as bridges and measuring corrosion acceleration of corrosive environments.

  For example, a structure such as a bridge inevitably suffers from a phenomenon in which corrosion progresses and strength as a structure decreases while being exposed to wind and rain for a long time.

  Therefore, in such a structure, it is necessary to regularly monitor the corrosion of the structural member and measure the corrosion acceleration of the corrosive environment. The measurement of the property had to rely on visual appearance inspection and inspection by hammering.

  However, such visual inspections and visual inspections by hammering as described above must be performed manually on site, and there is a problem that it requires a great deal of cost to maintain and manage structures such as bridges. .

  The present invention has been made in view of the above problems, and automatically and continuously monitors corrosion of structures such as bridges and measures corrosion promotion of corrosive environments even from a central monitoring center far away from the site. It is an object of the present invention to provide a corrosion monitoring device that can be carried out easily and can significantly reduce the labor cost related to the maintenance of the structure.

  Note that the corrosion monitoring apparatus described in the present application does not correspond to any of the conventional techniques of the above-described corrosion monitoring apparatus, and as far as the applicant knows, there is no known example similar to the present application, so it is disclosed at the time of the present application. No prior art document information should be held.

  In order to solve the above problems, the present invention has an optical fiber core and a clad, and a strain-measuring optical fiber core that is tensioned in the longitudinal direction, and the strain due to the tension applied to the strain-measuring optical fiber core is maintained. And a corrosion monitoring member joined to the strain-measuring optical fiber core, and the pump light composed of discontinuous laser light is incident on the optical fiber core of the strain-measuring optical fiber core to A scattered light analyzer that generates scattered light derived from strain and detects the scattered light from the optical fiber core to analyze the strain of the optical fiber core wire for strain measurement. The scattered light analyzer is strain-measured to be relaxed when the corrosion monitoring member is corroded. It is corrosion monitoring apparatus according to claim which is detectably configuration changes in the distortion of the optical fiber core wire.

  According to the present invention, the corrosion monitoring member is joined to the strain measurement optical fiber core wire so as to keep the strain of the strain measurement optical fiber core wire. The tension previously applied to the optical fiber core wire for measurement is relaxed and the strain is reduced.

  And since the scattered light analyzer connected to the optical fiber core wire for strain measurement via the optical fiber core wire for communication can detect the change in the strain of the optical fiber core wire for strain measurement, the central monitoring far away from the site Even from a center or the like, it becomes possible to automatically and continuously perform the monitoring of the corrosion of structures such as bridges and the measurement of the corrosion acceleration of the corrosive environment. As a result, it is not necessary to carry out on-site visual inspections and inspections, so that labor costs related to the maintenance of structures can be greatly reduced.

  Here, it is preferable that the corrosion monitoring member is configured to continuously restrain the strain-measuring optical fiber core wire.

  In this way, since the corrosion monitoring member continuously restrains the strain measuring optical fiber core wire, the corrosion monitoring member is within the range of continuously restraining the strain measuring optical fiber core wire. In any part, it is possible to accurately determine the position where the corrosion has occurred and the degree of the corrosion.

  The corrosion monitoring member is preferably configured to continuously restrain the strain measuring optical fiber core by being formed as a coating layer of the strain measuring optical fiber core.

  In this way, it is possible to realize a highly accurate corrosion monitoring apparatus that is easy to store and handle with a simple configuration in which the corrosion monitoring member is formed as a coating layer for the strain measurement optical fiber core wire.

  Further, the corrosion monitoring member is formed as a plate member for sandwiching the strain-measuring optical fiber core wire so as to continuously restrain the strain-measuring optical fiber core wire. The corrosion monitoring device described.

  In this way, it is possible to realize a highly accurate corrosion monitoring device that is easy to store and handle with a simple configuration in which the corrosion monitoring member is formed as a plate member that sandwiches the strain-measuring optical fiber core wire. Moreover, attachment to a structure becomes easy.

  The corrosion monitoring member is preferably configured to intermittently restrain the strain-measuring optical fiber core wire.

  In this way, since there is no need to continuously restrain the strain-measuring optical fiber core wire, the cost for manufacturing the corrosion monitoring device can be reduced, and an inexpensive corrosion monitoring device can be realized.

  In this case, since the strain of the optical fiber core wire for strain measurement is uniform within the range between the constraints, the position within this range cannot be specified, but any part within the range If corrosion occurs, uniform strain changes appear in the strain-measuring optical fiber core, so that it can be determined that corrosion has occurred within this range.

  Thus, when it is not necessary to accurately determine the position where corrosion has occurred, the cost for manufacturing the corrosion monitoring device can be reduced by intermittently constraining the strain measurement optical fiber core wire to the corrosion monitoring member. Therefore, an inexpensive corrosion monitoring device can be realized.

  The corrosion monitoring member is preferably formed in a tubular shape, and the drawn portion of the tubular corrosion monitoring member is preferably configured to intermittently restrain the strain-measuring optical fiber core wire.

  In this way, the corrosion monitoring member is formed into a tubular shape, and the strain measurement optical fiber core wire is intermittently restrained by the drawing portion of the tubular corrosion monitoring member. It is possible to reduce the manufacturing cost and realize an inexpensive corrosion monitoring apparatus.

  The corrosion monitoring device according to the present invention is provided substantially in parallel with the strain-measuring optical fiber core wire, and includes a temperature-measuring optical fiber core wire having an optical fiber core and a clad, and the temperature-measuring optical fiber core wire for corrosion monitoring. It is preferable to further include strain buffering means for holding the member displaceably.

  In this way, since the strain buffering means holds the temperature measuring optical fiber core so as to be displaceable with respect to the corrosion monitoring member, the temperature measuring optical fiber core can be kept in a state with little distortion. As a result, accurate temperature measurement with little influence of strain can be performed. Since the temperature measurement result of the strain-measuring optical fiber core wire can be accurately corrected using the temperature measurement result, the degree of corrosion can be determined with higher accuracy.

  Further, the strain buffer means includes a synthetic resin tube for holding the temperature measuring optical fiber core wire in the corrosion monitoring member, and the synthetic resin tube has the temperature measuring optical fiber core wire as a corrosion monitoring member. On the other hand, it is preferable to hold it smoothly so that it can be displaced.

  In this way, the synthetic resin pipe is provided in the corrosion monitoring member, and the optical fiber core wire for temperature measurement is held inside the synthetic resin pipe. The temperature correction of the measurement result of the optical fiber core wire for strain measurement can be performed.

  The corrosion monitoring member is preferably joined to a strain-measuring optical fiber core wire in a composite / reinforced state by a reinforcing material.

  By doing so, since the strain-measuring optical fiber core wire is reinforced and reinforced by the reinforcing material, an optical fiber core wire having insufficient strength alone can be used as the strain-measuring optical fiber core wire.

  As described above, according to the present invention, it is possible to automatically and continuously monitor corrosion of structures such as bridges even from a central monitoring center far away from the site. As a result, there is no need to manually perform appearance inspections and inspections on site, so that the labor cost related to the maintenance of the structure can be greatly reduced.

  Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is a perspective view showing a configuration of a corrosion monitoring apparatus 1 according to the first embodiment of the present invention, and FIG. 2 is a corrosion monitoring unit 2 of the corrosion monitoring apparatus 1 according to the first embodiment of the present invention. It is a perspective view which shows the structure. FIG. 3 is a cross-sectional view showing a configuration of the corrosion monitoring unit 2 of the corrosion monitoring apparatus 1 according to the first embodiment of the present invention, and FIG. 4 is a perspective view showing a manufacturing procedure of the corrosion monitoring unit 2. It is.

  Referring to FIG. 1, the illustrated corrosion monitoring apparatus 1 according to the first embodiment of the present invention is an apparatus configured to monitor and measure the corrosion of a structure of a bridge 3 at a plurality of points, for example. The plurality of corrosion monitoring units 2 and the scattered light analyzing device 6 are provided, and the plurality of corrosion monitoring units 2 and the scattered light analyzing device 6 are optically connected to each other via a communication optical fiber core wire 7. It is connected.

  The corrosion monitoring unit 2 is a device that is installed at a plurality of points along the longitudinal direction of the bridge 3 and monitors and measures the corrosion of the structure of the bridge 3. As shown in FIG. An optical fiber core wire 4 and a corrosion monitoring member 5 joined to the strain measuring optical fiber core wire 4 are provided. The strain-measuring optical fiber core wire 4 is optically connected to the scattered light analyzer 6 (FIG. 1) via a communication optical fiber core wire 7.

  As will be described in detail later, the scattered light analyzer 6 is configured to detect a change in the strain of the optical fiber core wire 4 for strain measurement that is relaxed when the corrosion monitoring member 5 is corroded. The degree of corrosion of the structure of the bridge 3 made of the same material as that of the corrosion monitoring member 5 can be estimated by the change in the strain of the optical fiber core wire 4 for strain measurement based on the corrosion of the member 5.

  The bridge 3 (FIG. 1) is a structure that should be monitored for corrosion. In this embodiment, the corrosion monitoring unit 2 monitors the steel material used for the bridge 3.

  Although not shown, the strain-measuring optical fiber core wire 4 includes an optical fiber core that transmits light, a cladding that reflects light, and a coating layer that protects the optical fiber core and the cladding from the outside. Combined and reinforced. As shown in FIG. 4, the strain-measuring optical fiber core wire 4 is previously strained in the longitudinal direction, and is sandwiched and joined by a corrosion monitoring member 5 comprising an upper member 5a and a lower member 5b. Thus, the applied strain remains after the corrosion monitoring member 5 is joined.

  In addition, these strain-measuring optical fiber core wires 4 of the corrosion monitoring unit 2 are optically connected to the connecting optical fiber core wires 7 respectively to form one continuous optical path.

  The corrosion monitoring member 5 is a member joined to the strain measuring optical fiber core 4 so as to keep the strain due to the tension applied to the strain measuring optical fiber core 4, and the structure of the bridge 3 to be monitored for corrosion. The same material as the object is selected. In the present embodiment, a steel plate having the same composition as the steel material constituting the bridge 3 is targeted.

  In this embodiment, as shown in FIG. 4, the corrosion monitoring member 5 has an upper member 5a and a lower member 5b that sandwich the optical fiber core wire 4 for strain measurement, and is a steel plate material joined to each other. The strain measuring optical fiber core wire 4 is continuously constrained.

  The scattered light analyzing device 6 (FIG. 1) makes the pump light composed of discontinuous laser light incident on the optical fiber core of the strain-measuring optical fiber core 4 to generate the scattered light derived from the strain of the strain-measuring optical fiber core wire 4. The optical fiber core 4 is generated and the scattered light of the optical fiber core is detected to analyze the distortion of the optical fiber core wire 4 for strain measurement, and is optically connected to the optical fiber core wire 4 for strain measurement via the optical fiber core wire 7 for connection. ing.

  The scattered light analyzer 6 is configured to be able to detect a change in the strain of the strain-measuring optical fiber core wire 4 that is relaxed in a state where the corrosion monitoring member 5 is corroded, and the analysis result is stored in an adjacent personal computer. In this personal computer, the degree of corrosion at each point is displayed as a value proportional to the change in strain of the strain-measuring optical fiber core wire 4.

  The connecting optical fiber core wire 7 transmits laser light from the scattered light analyzing device 6 and scattered light from the strain measuring optical fiber core wire 4, and light that transmits light in the same manner as the strain measuring optical fiber core wire 4. It has a fiber core, a clad that reflects light, and a coating layer that protects the optical fiber core and the clad from the outside. The scattered light analyzer 6 and the strain-measuring optical fiber core 4 are optically connected to each other.

  Next, with reference to FIG. 5 and FIG. 6, the operation of the corrosion monitoring apparatus 1 according to the embodiment of the present invention will be described.

  FIG. 5 is a cross-sectional view showing the operation of the corrosion monitoring unit 2. FIG. 5A shows a strain-measuring optical fiber core wire 4 in a length D before strain is applied, and FIG. Each of the strain-measuring optical fiber core wires 4 has a length of D + ΔD after tension is applied in the direction. (C) shows the strain-measuring optical fiber core 4 in a state where the corrosion monitoring member 5 is joined in a state where the strain is applied to the strain-measuring optical fiber core 4, and (d) shows the strain-measuring optical fiber core. 4 shows a state in which the stress due to the strain of 4 and the stress due to the strain of the corrosion monitoring member 5 are balanced and contracted by the dimension d from the state of (c). Each of these shows a state in which the dimension is contracted by δ due to corrosion and the strain of the optical fiber core 4 for strain measurement is relaxed.

  Here, FIG. 6 is a graph showing the relationship between the frequency shift of Brillouin scattered light in the strain-measuring optical fiber core wire 4 and the strain in the strain-measuring optical fiber core wire 4.

  When the scattered light analyzer 6 enters the strain measurement optical fiber core wire 4 of the corrosion monitoring unit 2 via the communication optical fiber core wire 7, the scattered light derived from the strain of the strain measurement optical fiber core wire 4 is generated. By detecting this scattered light, it becomes possible to determine the strain of the optical fiber core wire 4 for strain measurement and easily measure the degree of corrosion corresponding to this strain.

  In the present embodiment, the scattered light analyzing apparatus 6 indicates that the frequency shift of Brillouin scattered light in the strain-measuring optical fiber core 4 and the strain in the strain-measuring optical fiber 4 are proportional to each other as shown in FIG. Utilizing this, the strain of the optical fiber core wire 4 for strain measurement is analyzed. FIG. 6 is a graph of the frequency shift of the Brillouin scattered light when the frequency of the laser light is 493 MHz and the wavelength is 1.55 μm. Scattered light reaches the scattered light analyzer 6 in the opposite direction from the optical fiber core wire 4 for strain measurement. The place where the distortion is generated is identified from the time delay of the Brillouin scattered light. Further, the frequency shift of the Brillouin scattered light is detected, and the distortion at the location is analyzed from the relationship of FIG.

  Then, this analysis data is input to the adjacent personal computer 6a, and in this personal computer, the degree of corrosion at each point is displayed as a value proportional to the strain change of the strain-measuring optical fiber core wire 4, and the value of this strain is displayed. When the value falls below a certain value, it can be seen that the corrosion has progressed above the allowable value at that point.

  In this way, the corrosion monitoring apparatus 1 can monitor and measure the corrosion of the structure of the bridge 3 at a plurality of points.

  As described above, according to the corrosion monitoring apparatus 1 according to the first embodiment of the present invention, the corrosion monitoring member 5 is attached to the strain measuring optical fiber core 4 so as to keep the strain of the strain measuring optical fiber core 4. When the strength of the corrosion monitoring member 5 is reduced due to corrosion, the tension applied in advance to the strain-measuring optical fiber core wire 4 is relaxed and strain is reduced.

  And since the scattered light analyzer 6 connected to the strain-measuring optical fiber core wire 4 via the communication optical fiber core wire 7 can detect the change in the strain of the strain-measuring optical fiber core wire 4, it is far from the site. Even from a remote central monitoring center, it is possible to automatically monitor the corrosion of structures such as the bridge 3 and measure the corrosion acceleration of the corrosive environment. As a result, it is not necessary to carry out on-site visual inspections and inspections, so that labor costs related to the maintenance of structures can be greatly reduced.

  Further, since the corrosion monitoring member 5 continuously restrains the strain measuring optical fiber core wire 4, the corrosion monitoring member 5 of the corrosion monitoring member 5 is within a range in which the strain measuring optical fiber core wire 4 is continuously restrained. In any part, it is possible to accurately determine the position where the corrosion has occurred and the degree of the corrosion.

  In addition, the corrosion monitoring apparatus 1 can be realized with a simple configuration in which the corrosion monitoring member 5 is formed as a plate member that sandwiches the strain-measuring optical fiber core wire 4 and is easily stored and handled. Moreover, attachment to a structure becomes easy.

  In addition, since the strain-measuring optical fiber core wire is reinforced and reinforced by a reinforcing material, an optical fiber core wire that is insufficient in strength alone can be used as the strain-measuring optical fiber core wire.

  Next, a corrosion monitoring unit 22 according to the second embodiment of the present invention will be described with reference to FIGS. FIG. 7 is a perspective view showing the configuration of the corrosion monitoring unit 22 according to the second embodiment of the present invention, and FIG. 8 is a cross-sectional view showing the configuration of the corrosion monitoring unit 22 according to the second embodiment of the present invention. FIG. In the following description, the same members as those in the corrosion monitoring apparatus 1 according to the first embodiment of the present invention are denoted by the same reference numerals, and redundant descriptions are omitted.

  As shown in FIGS. 7 and 8, the corrosion monitoring unit 22 according to the second embodiment of the present invention is different from the corrosion monitoring unit 2 according to the first embodiment. Further provided is strain buffering means 9 for holding the temperature measuring optical fiber core wire 8 so as to be displaceable with respect to the corrosion monitoring member 5.

  Similar to the strain-measuring optical fiber core wire 4, the temperature-measuring optical fiber core wire 8 has an optical fiber core that transmits light, a clad that reflects light, and a coating layer that protects the optical fiber core and the clad from the outside. is doing. The temperature-measuring optical fiber core 8 is connected to a channel other than the strain-measuring optical fiber core 4 in the scattered light analyzer 6 via a communication optical fiber core 7a.

  Unlike the strain-measuring optical fiber core wire 4, the temperature-measuring optical fiber core wire 8 is not distorted in the longitudinal direction.

  The strain buffering means 9 includes a synthetic resin tube 10 for holding the temperature measuring optical fiber core wire 8 in the corrosion monitoring member 5, and the synthetic resin tube 10 holds the temperature measuring optical fiber core wire 8 smoothly. By doing so, the temperature measuring optical fiber core wire 8 can be displaced with respect to the corrosion monitoring member 5. That is, the temperature measuring optical fiber core 8 is not joined to the corrosion monitoring member 5 by the strain buffering means 9 provided between the temperature measuring optical fiber core 8 and the corrosion monitoring member 5, and is not a member for corrosion monitoring. Since it is held displaceable with respect to 5, the distortion is reduced.

  Thus, according to the corrosion monitoring unit 22 according to the second embodiment, the optical fiber core wire 8 for temperature measurement is further provided, and the strain buffering means 9 attaches the optical fiber core wire 8 for temperature measurement to the corrosion monitoring member 5. Therefore, the temperature measuring optical fiber core wire 8 can be kept in a state with little distortion. As a result, accurate temperature measurement with little influence of strain can be performed.

  In addition, the strain buffering means 9 can be realized with a simple configuration in which the synthetic resin tube 10 is provided in the corrosion monitoring member 5 and the temperature measuring optical fiber core wire 8 is held inside the synthetic resin tube 10 to accurately In addition, the temperature correction of the measurement result of the strain-measuring optical fiber core 4 can be performed. As a result, the temperature of the measurement result of the strain-measuring optical fiber core wire 4 can be accurately corrected using the temperature measurement result, so that the degree of corrosion can be determined with higher accuracy.

  Moreover, with reference to FIG. 9, the corrosion monitoring unit 32 which concerns on the 3rd Embodiment of this invention is demonstrated. FIG. 9 is a perspective view showing a configuration of a corrosion monitoring unit 32 according to the third embodiment of the present invention. In the following description, the same members as those in the corrosion monitoring unit 2 according to the first embodiment of the present invention are denoted by the same reference numerals, and redundant descriptions are omitted.

  As shown in FIG. 9, the corrosion monitoring unit 32 according to the third embodiment of the present invention is different from the corrosion monitoring unit 2 according to the first embodiment in that the corrosion monitoring member 35 includes a strain measurement optical fiber core 4. It is comprised so that it may restrain intermittently. That is, in the corrosion monitoring unit 32 according to the third embodiment, the corrosion monitoring member 35 is formed in a tubular shape, and the drawing portion 36 of the tubular corrosion monitoring member 35 connects the strain-measuring optical fiber core wire 4. It is designed to be restrained intermittently.

  As described above, according to the corrosion monitoring unit 32 according to the third embodiment, since it is not necessary to continuously restrain the strain-measuring optical fiber core wire 4, the cost for manufacturing the corrosion monitoring unit 32 can be reduced and reduced. A simple corrosion monitoring device can be realized.

  In this case, since the strain of the optical fiber core 4 for strain measurement becomes uniform within the range between the constraints, the position within this range cannot be specified. If corrosion occurs in the portion, a uniform change in strain appears in the strain-measuring optical fiber core wire 4. Therefore, it can be determined that corrosion has occurred within this range.

  That is, when it is not necessary to accurately determine the position where corrosion has occurred, the strain monitoring optical fiber core wire 4 is intermittently restrained by the corrosion monitoring member 35 as described above, thereby manufacturing the corrosion monitoring device. Therefore, an inexpensive corrosion monitoring device can be realized.

  In particular, according to the corrosion monitoring unit 32 according to the third embodiment, the corrosion monitoring member 35 is formed in a tubular shape, and the strain measurement optical fiber core wire 4 is formed by the drawing portion 36 of the tubular corrosion monitoring member 35. With a simple configuration that restrains intermittently, it is possible to reduce the cost for manufacturing the corrosion monitoring apparatus and to realize an inexpensive corrosion monitoring apparatus.

  The above-described embodiments are merely examples of preferred specific examples of the present invention, and the present invention is not limited to the above-described embodiments.

  For example, the bridge 3 is not limited to the railway bridge 3 such as a Shinkansen. It can also be applied to automobiles and other bridges 3. Moreover, as long as it is a structure which should monitor corrosion, it is applicable not only to the bridge 3 but to any structure. Further, the present invention can be applied to any environment as long as the corrosion acceleration should be measured.

  The corrosion monitoring member 5 is not limited to a steel plate. It can be applied to any material as long as it is the same material as the structure to be monitored or measured for corrosion.

  Further, the corrosion monitoring member 5 is not necessarily formed as a plate material. For example, FIG. 10 shows a perspective view of a corrosion monitoring unit 42 according to a modification of the first embodiment of the present invention, and shows a state in which a metal coating layer 45 is provided as a corrosion monitoring member. FIG. 11 is a perspective view of a corrosion monitoring unit 52 according to another modification of the first embodiment of the present invention, in which a tape-like covering layer 55 of a fiber material is provided as a corrosion monitoring member. Indicates the state. FIG. 12 shows a modification of the corrosion monitoring unit 62 according to a modification of the second embodiment of the present invention, and shows a state in which a metal coating layer 65 is provided as a corrosion monitoring member. In the corrosion monitoring units 42, 52, and 62 according to these modified examples, the corrosion monitoring members 45, 55, and 65 are formed as coating layers for the strain measuring optical fiber core 4, respectively, so that the strain measuring optical fiber core 4. Are constrained continuously.

  In this way, it is possible to realize a highly accurate corrosion monitoring apparatus that is easy to store and handle with a simple configuration in which the corrosion monitoring member is formed as a coating layer for the strain-measuring optical fiber core wire 4.

  Various scattered light analyzers 6 can also be used as the scattered light analyzer 6, and it is not always necessary to be based on the relationship between the frequency shift of the Brillouin scattered light and the strain of the optical fiber core 4 for strain measurement. Various kinds of scattered light such as Raman scattered light can be employed. In addition, laser beams having various frequencies can be used.

  Further, the strain buffering means 9 is not limited to the synthetic resin tube 10 that holds the optical fiber core wire 8 for temperature measurement inside. As long as the temperature measuring optical fiber core wire 8 is held so as to be displaceable with respect to the corrosion monitoring member 5, various design changes are possible.

  Further, in the corrosion monitoring unit 32 according to the third embodiment of the present invention, as shown in the drawing, the corrosion monitoring member 35 is formed in a tubular shape, and the drawing portion 36 of the tubular corrosion monitoring member 35 is provided. The strain-measuring optical fiber core wire 4 is not limited to those that are intermittently restrained. For example, FIG. 13 shows a corrosion monitoring unit 72 according to a first modification of the third embodiment of the present invention. In the corrosion monitoring unit 72 according to the first modification of the third embodiment, the corrosion monitoring member 75 is formed as a flexible cladding tube that gently covers the strain-measuring optical fiber core wire 4. Since the member 75 for monitoring corrosion of the cladding tube is hardened with the resin 76 in some places, the optical fiber core wire 4 for strain measurement is intermittently restrained.

  FIG. 14 is a perspective view showing a corrosion monitoring unit 82 according to a second modification of the third embodiment of the present invention, and FIG. 15 is an exploded perspective view thereof.

  As shown in FIGS. 14 and 15, in the corrosion monitoring unit 72 according to the second embodiment of the third embodiment, the corrosion monitoring unit 2 according to the first embodiment of the present invention in FIG. The corrosion monitoring member 5 is intermittently constrained to the strain measuring optical fiber core 4 by a bonding material 81 such as a synthetic resin so as to keep the strain due to the tension applied to the strain measuring optical fiber core 4.

  FIG. 16 is a perspective view showing a corrosion monitoring unit according to a third modification of the third embodiment of the present invention.

  As shown in FIG. 16, in the corrosion monitoring unit 92 according to the third modification of the third embodiment, in the corrosion monitoring unit 22 according to the second embodiment of the present invention in FIG. 5 is intermittently constrained to the strain measuring optical fiber core 4 by a bonding material 91 such as a synthetic resin so as to keep the strain due to the tension applied to the strain measuring optical fiber core 4.

  According to the corrosion monitoring units 72, 82, and 92 according to the first to third modifications of the third embodiment, since the structure is simple, the cost for manufacturing the corrosion monitoring device can be further reduced, and the cost can be reduced. A simple corrosion monitoring device can be realized.

  Similarly, in the corrosion monitoring unit according to the modification of the first embodiment shown in FIGS. 10 and 11, it is also possible to intermittently restrain the strain-measuring optical fiber core wire 4.

  In addition, it goes without saying that various design changes are possible within the scope of the claims of the present invention.

It is a perspective view which shows the structure of the corrosion monitoring apparatus which concerns on the 1st Embodiment of this invention. It is a perspective view which shows the structure of the corrosion monitoring unit of the corrosion monitoring apparatus which concerns on the 1st Embodiment of this invention. It is sectional drawing which shows the structure of the corrosion monitoring unit of the corrosion monitoring apparatus which concerns on the 1st Embodiment of this invention. It is a perspective view which shows the point of manufacture of a corrosion monitoring unit. It is sectional drawing which shows the effect | action of a corrosion monitoring unit, (a) is the strain measurement optical fiber core wire 4 of the state before the strain is added in the state of D, (b) is tension added to the longitudinal direction beforehand. The optical fiber core wires for strain measurement in a state where the length after being formed becomes D + ΔD are shown. (C) shows a strain-measuring optical fiber core in a state where the corrosion monitoring member is joined in a state where the strain-measuring optical fiber core is distorted, and (d) shows the strain due to the strain of the strain-measuring optical fiber core. The stress balances with the stress due to the strain of the corrosion monitoring member, and (c) shows a state where the strain shrinks by the dimension and (e) shows that the corrosion monitoring member corrodes and the dimension shrinks only. And the state where the distortion of the optical fiber core wire for strain measurement is alleviated is shown. It is a graph which shows the relationship between the frequency shift of the Brillouin scattered light in the optical fiber core line for distortion measurement, and the distortion of the optical fiber core line for distortion measurement. It is a perspective view which shows the structure of the corrosion monitoring unit which concerns on the 2nd Embodiment of this invention. It is sectional drawing which shows the structure of the corrosion monitoring unit which concerns on the 2nd Embodiment of this invention. It is a perspective view which shows the structure of the corrosion monitoring unit which concerns on the 3rd Embodiment of this invention. The perspective view of the corrosion monitoring unit which concerns on the modification of the 1st Embodiment of this invention is shown, and the state by which the metal coating layer was provided as a member for corrosion monitoring is shown. The perspective view of the corrosion monitoring unit which concerns on another modification of the 1st Embodiment of this invention is shown, and the state provided with the tape-shaped coating layer of the fiber material as a corrosion monitoring member is shown. The modification of the corrosion monitoring unit which concerns on the modification of the 2nd Embodiment of this invention is shown, and the state by which the metal coating layer was provided as a member for corrosion monitoring is shown. It is a perspective view which shows the corrosion monitoring unit which concerns on the 1st modification of the 3rd Embodiment of this invention. It is a perspective view which shows the corrosion monitoring unit which concerns on the 2nd modification of the 3rd Embodiment of this invention. It is a disassembled perspective view which shows the corrosion monitoring unit which concerns on the 2nd modification of the 3rd Embodiment of this invention. It is a perspective view which shows the corrosion monitoring unit which concerns on the 3rd modification of the 3rd Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Corrosion monitoring apparatus 4 Strain measurement optical fiber core 5 Corrosion monitoring member 6 Scattered light analyzer 7 Communication optical fiber core 8 Temperature measurement optical fiber core 9 Strain buffering means 10 Synthetic resin pipe 36 Drawing part

Claims (9)

An optical fiber core wire for strain measurement having an optical fiber core and a clad, and having a tension applied in the longitudinal direction;
A corrosion monitoring member joined to the strain-measuring optical fiber core so as to keep strain due to the tension applied to the strain-measuring optical fiber core,
Pump light consisting of discontinuous laser light is incident on the optical fiber core of the optical fiber core for strain measurement to generate scattered light derived from the strain of the optical fiber core for strain measurement, and the scattered light of the optical fiber core is detected. The optical fiber core wire for strain measurement is optically connected to the scattered light analyzer for analyzing the strain of the optical fiber core wire for strain measurement via the optical fiber core wire for connection,
The scattered light analyzer is configured to be able to determine the corrosion of the corrosion monitoring member by detecting a change in strain of the optical fiber core wire for strain measurement that is relaxed in a state where the corrosion monitoring member is corroded. Corrosion monitoring device characterized by.   The corrosion monitoring apparatus according to claim 1, wherein the corrosion monitoring member is configured to continuously restrain the strain-measuring optical fiber core wire.   The corrosion according to claim 2, wherein the corrosion monitoring member is configured to continuously restrain the strain-measuring optical fiber core wire by being formed as a coating layer of the strain-measuring optical fiber core wire. Monitoring device.   The said corrosion monitoring member is comprised as a board | plate material which clamps the optical fiber core wire for strain measurement, and is comprised so that the optical fiber core wire for strain measurement may be restrained continuously. Corrosion monitoring device.   The corrosion monitoring apparatus according to claim 1, wherein the corrosion monitoring member is configured to intermittently restrain the strain measuring optical fiber core wire.   6. The corrosion monitoring member is formed in a tubular shape, and the drawn portion of the tubular corrosion monitoring member is configured to intermittently restrain the strain-measuring optical fiber core wire. The corrosion monitoring device described in 1. A temperature-measuring optical fiber core line provided substantially parallel to the strain-measuring optical fiber core line and having an optical fiber core and a cladding;
A strain buffering means for holding the optical fiber core wire for temperature measurement so as to be displaceable with respect to the corrosion monitoring member;
The corrosion monitoring apparatus according to any one of claims 1 to 6, further comprising: The strain buffer means includes a synthetic resin tube in the corrosion monitoring member that holds the optical fiber core for temperature measurement inside,
8. The corrosion monitoring device according to claim 7, wherein the synthetic resin tube holds the optical fiber core for temperature measurement smoothly and displaceably with respect to the member for corrosion monitoring.   9. The corrosion monitoring apparatus according to claim 1, wherein the corrosion monitoring member is joined to a strain-measuring optical fiber core wire in a composite and reinforced state by a reinforcing material.

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